Electrophoretic karyotyping of wild-type and mutant Trichoderma longibrachiatum (reesei) strains

Arja L. Mäntylä*, K. Hannele Rossi, Sirpa A. Vanhanen, Merja E. Penttilä, Pirkko L. Suominen, K. M Helena Nevalainen

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

63 Citations (Scopus)


An electrophoretic karyotype of Trichoderma longibrachiatum (reesei) was obtained using contourclamped homogeneous electric field (CHEF) gel electrophoresis. Seven chromosomal DNA bands were separated in the wild-type T. longibrachiatum strain QM6a. The sizes of the chromosomal DNA bands ranged from 2.8 to 6.9 Mb, giving an estimated total genome size of about 33 Mb. The electrophoretic karyotype of the strain QM6a was compared to three hyper-cellulolytic mutant strains, QM9414, RutC30 and VTT-D-79125. The chromosome pattern of the mutant QM9414 was quite similar to that of the wild-type QM6a except that the smallest chromosome differed somewhat in size. The VTT-D-79125 and RutC30 strains, which have undergone several mutagenesis steps, showed striking differences in their karyotype compared to the initial parent. The chromosomal DNA bands were identified using the previously characterized T. longibrachiatum genes (egl1, egl2, cbh1, cbh2, pgk1, rDNA) and random clones isolated from a genomic library. In all strains the cellulase genes cbh1, cbh2 and egl2 were located in the same linkage group (chromosome II in the wild-type), while the main endoglucanase, egl1, hybridized to another chromosomal DNA band (chromosome VI in the wild-type).

Original languageEnglish
Pages (from-to)471-477
Number of pages7
JournalCurrent Genetics
Issue number6
Publication statusPublished - May 1992
Externally publishedYes


  • Cellulase genes
  • Chromosomal rearrangements
  • Chromosome-specific clones
  • Filamentous fungi


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